hypnosec writes: The Linux Foundation’s UEFI secure boot pre-bootloader is still in the works and has been modified substantially so that it allows any Linux versions to boot through UEFI secure boot. The reason for modifying the pre-bootloader was that the current version of the loader wouldn’t work with Gummiboot which was designed to boot kernels using BootServices->LoadImage(). Further the original pre-bootloader had been written using “PE/Coff link loading to defeat the secure boot checks.” As it stands, anything run by the original pre-bootloader must also be link-loaded to defeat secure boot and Gummiboot, which is not a link-loader, didn't work in this scenario. This is the reason a re-write of the pre-bootloader was required and now it supports booting of all versions of Linux.Link to Original Source